3 Dec 2015 AEDT
1 Feb 2016 AEDT


This consultation is now closed.

Submissions were received from a number of individuals and entities from the hot water and gas industries, government bodies as well as technical experts with an interest in this topic.

Submissions covered a broad range of technical issues about the operation and effectiveness of a zoned map to present the performance of solar hot water systems.  

Many submissions were supportive of the objectives of this work.  A number of submissions did not support the proposals and identified a number of concerns, including for example whether a zoned map for solar water systems would be worthwhile, practical or cost effective.

At this stage E3 has deferred further work in this area pending the completion of higher priority tasks for delivering energy efficiency benefits to the Australian community.  


The Zoned Map for Solar Water Heaters report outlines the development of a zoned map for Solar Water Heaters (SWH) and documents the methodology used. This work relates to the development of a Zoned Energy Rating Label (ZERL) for water heaters. For more information about the ZERL refer to the labelling page.

The map characterises the performance of SWHs in differing regions of Australia and New Zealand. With the intention to display the map on a ZERL it will enable comparisons across and within all residential water heater categories.

Comments and views are sought on the overall approach and technical elements of the methodology for a zoned map for solar water heaters. Important considerations are:

  • The overall methodology;
  • The selection of reference cities for future performance modelling;
  • Selection of reference solar water heater technology to be used for the zoned map; and
  • The selection of zone boundaries.

What is proposed in the report?

The zoned map for solar water heaters presented in this paper consists of three consolidated areas classified as:

  • Hot zone: an area where a reference solar water heater has energy savings greater than 80% compared to a reference electric water heater system.
  • Mixed zone: an area where the expected savings are between 60% and 80%.
  • Cold zone: an area where the expected savings are below 60%.

When modelled to deliver a medium load (as specified in AS/NZS 4234), reference solar water heaters in the hot zone have been shown to require up to a maximum of 20% auxiliary energy from either electricity or gas. Similarly, a modelled SWH would require up to a maximum of 40% auxiliary energy in the ‘mixed zone’ and up to a maximum of 100% auxiliary energy in the ‘cold’ zone.

The approach adopts high resolution spatial zoning whereby the 69 Nationwide House Energy Rating Scheme (NatHERS) climate regions from Australia and the 18 New Zealand climate files will be used. Using these regions and their climate files will allow for improved spatial resolution on the zoned map for SWHs and the ability to drill down for location specific information on the web or via mobile application.

An example of what the map with the three zones could look like is demonstrated below in the stylised map.

Figure above is an example of a stylised zoned map for solar hot water systems.

Relevant Documents


Have your say

The entry period for submissions closed on 1 February 2016.

Questions about the Zoned Map for Solar Water Heaters and the development process can be directed to Peter.McLoughlin@industry.gov.au.